Dynamic Force Response of an Open-Ended Squeeze Film Damper

1993 ◽  
Vol 115 (2) ◽  
pp. 341-346 ◽  
Author(s):  
L. A. San Andres ◽  
G. Meng ◽  
S. Yoon
Keyword(s):  
Pressure Field ◽  
Tangential Force ◽  
Radial Force ◽  
Squeeze Film ◽  
Dynamic Force ◽  
Flow Conditions ◽  
Squeeze Film Damper ◽  
Inertial Flow ◽  
Experimental Pressure ◽  
Lubricant Viscosity

The effects of whirl frequency and lubricant viscosity on the experimental pressure field and film forces in an open-ended squeeze film damper test rig are presented. The measurements refer to circular centered journal motion of amplitude equal to one half the damper clearance (ε = 0.5). The whirl frequency varied between 16 Hz and 85 Hz, while the lubricant temperature increased from 25°C to 45°C. The damper operated with levels of external pressurization that supressed lubricant cavitation. The experimental results show conclusively that the radial film force is purely an inertial effect, i.e., it depends solely on the fluid density and the second power of the whirl frequency. The tangential film force shows a variation that depends on the viscous and inertial flow conditions in the squeeze film region. Correlation of experimental forces with conventional SFD models shows the radial force to be π times larger than the theoretical prediction, while the tangential force correlates well for low whirl frequencies and large lubricant viscosities.

scholarly journals Dynamic Force Response of an Open Ended Squeeze Film Damper

1991 ◽  
Author(s):  
L. A. San Andres ◽  
G. Meng ◽  
S. Yoon
Keyword(s):  
Pressure Field ◽  
Tangential Force ◽  
Radial Force ◽  
Squeeze Film ◽  
Dynamic Force ◽  
Flow Conditions ◽  
Squeeze Film Damper ◽  
Inertial Flow ◽  
Experimental Pressure ◽  
Lubricant Viscosity

The effects of whirl frequency and lubricant viscosity on the experimental pressure field and film forces in an open ended squeeze film damper test rig are presented. The measurements refer to circular centered journal motion of amplitude equal to one half the damper clearance (ε=0.5). The whirl frequency varied between 16Hz to 85Hz, while the lubricant temperature increased from 25°C to 45°C. The damper operated with levels of external pressurization which supressed lubricant cavitation. The experimental results show conclusivey that the radial film force is purely an inertial effect, i.e. it depends solely on the fluid density and the second power of the whirl frequency. The tangential film force shows a variation which depends on the viscous and inertial flow conditions in the squeeze film region. Correlation of experimental forces with conventional SFD models shows the radial force to be π times larger than the theoretical prediction, while the tangential force correlates well for low whirl frequencies and large lubricant viscosities.

Effect of a Circumferential Feeding Groove on the Dynamic Force Response of a Short Squeeze Film Damper

1994 ◽  
Vol 116 (2) ◽  
pp. 369-376 ◽  
Author(s):  
G. L. Arauz ◽  
L. San Andres
Keyword(s):  
Flow Model ◽  
Dynamic Pressure ◽  
Squeeze Film ◽  
Dynamic Force ◽  
Force Response ◽  
Squeeze Film Damper ◽  
Circumferential Groove ◽  
Damping Characteristics ◽  
Radial Forces ◽  
Lubricant Viscosity

The effect of a circumferential feeding groove on the dynamic force response of a short length, open end squeeze film damper is studied experimentally. Damper configurations with increasing groove depths and journal orbit radii were tested for several conditions of whirl frequency and lubricant viscosity. Significant levels of dynamic pressure were measured at the circumferential groove, and relatively large tangential (damping) forces are produced at the groove which contribute considerably to the damping characteristics of the SFD test articles. Radial forces of substantial magnitude are determined at the groove and at the thin film land where the squeeze film Reynolds number is typically less than 1. The circumferential groove is thought to induce an inertia like effect into the film land. The experimental results correlate well with the predictions from a groove volume-circumferential flow model developed.

Experimental Investigation on the Dynamic Pressure and Force Response of a Partially Sealed Squeeze Film Damper

1991 ◽  
Author(s):  
G. Meng ◽  
L. A. San Andres ◽  
J. M. Vance
Keyword(s):  
Rotational Speed ◽  
Dynamic Pressure ◽  
Tangential Force ◽  
Radial Force ◽  
Squeeze Film ◽  
Damping Force ◽  
Film Pressure ◽  
Squeeze Film Damper ◽  
Fluid Forces ◽  
Supply Pressure

Abstract The influence of rotational speed, oil temperature and supply pressure on the squeeze film pressure and fluid forces is investigated experimentally for a partially sealed squeeze film damper (SFD) test rig executing circular centered orbits. Experimental Tesults show that the sealed damper produces higher damping forces than an open end SFD, though it is more prone to produce oil cavitation. As a result, the peak-to-peak pressures and the tangential force (damping force) decrease with increasing rotational speed; while, the radial force (stiffhening force) becomes negative due to the large extent of the cavitation zone. The tangential force decreases and the radial force increases with increasing lubricant temperature. The squeeze film pressure and film force increase as the supply pressure rises. The film cavitation onset is determined by the level of supply pressure and rotational speed.

Application of the k-ε Turbulence Model to the Squeeze Film Damper

1987 ◽  
Vol 109 (1) ◽  
pp. 164-168 ◽  
Author(s):  
Chiao-Ping Ku ◽  
John A. Tichy
Keyword(s):  
High Speed ◽  
Transport Model ◽  
Tangential Force ◽  
Fluid Pressure ◽  
Radial Force ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Damping Force ◽  
Mean Velocity ◽  
Squeeze Film Damper

The one-dimensional squeeze film damper is modeled for high speed flow by using the two-equation (k-ε) turbulent transport model. The assumption is made that the fluid flow at each local region of the squeeze film damper has similar behavior to inertialess flow in a channel at comparable Reynolds number. Using the k-ε model, the inertialess channel flow case is solved. Based on this result, correlations are obtained for the mean velocity, inertia and viscous terms of the integrated momentum equation for the squeeze film damper. It is found that turbulence increases the magnitude of the fluid pressure and the tangential force, while fluid inertia causes a shift on the pressure creating a significant radial force. In applications, turbulence may be a beneficial effect, increasing the principal damping force; while inertia may be detrimental increasing the cross-coupling forces.

Experimental Pressures and Film Forces in a Squeeze Film Damper

1993 ◽  
Vol 115 (1) ◽  
pp. 134-140 ◽  
Author(s):  
G. L. Arauz ◽  
L. A. San Andres
Keyword(s):  
Tangential Force ◽  
Radial Force ◽  
Squeeze Film ◽  
Radial Clearance ◽  
Fluid Inertia ◽  
Damping Force ◽  
Inertia Effects ◽  
Squeeze Film Dampers ◽  
Tangential Forces ◽  
Lubricant Viscosity

The effect of whirl frequency and lubricant viscosity on the dynamic pressures and force response of an open end and a partially sealed squeeze film dampers (SFD) with a radial clearance of 0.38 mm is determined experimentally. The experiments are carried out in a damper test rig executing circular centered orbits and for whirl frequencies ranging from 33 to 83 Hz. The experimental results show that the sealed SFD configuration produces larger tangential forces than the open end SFD. The tangential (damping) force increases linearly with increasing whirl frequency. For this radial clearance fluid inertia effects in the damper are found to be negligible since the squeeze film Reynolds number is less than 1.20. Cavitation was observed in both damper configurations at high frequencies and high lubricant viscosities. This condition limited the rate of increment of the damping (tangential) force with increasing frequency and reduced the radial force when lubricant viscosity increased.

Experimental Study on the Effect of a Circumferential Feeding Groove on the Dynamic Force Response of a Sealed Squeeze Film Damper

1996 ◽  
Vol 118 (4) ◽  
pp. 900-905 ◽  
Author(s):  
G. L. Arauz ◽  
Luis San Andres
Keyword(s):  
Piston Ring ◽  
Dynamic Pressure ◽  
Squeeze Film ◽  
Dynamic Force ◽  
Force Response ◽  
Flow Conditions ◽  
Squeeze Film Damper ◽  
Circumferential Groove ◽  
Damping Characteristics ◽  
Radial Forces

The influence of a circumferential feeding groove on the dynamic force response of a sealed squeeze film damper is determined experimentally. The damper is sealed by means of a serrated piston ring located at the discharge end of the damper. Damper configurations with two different groove depths and journal orbit radii were tested at increasing whirl frequencies. Large levels of dynamic pressure were measured at the circumferential groove, and relatively large tangential (damping) forces are produced at the groove which contribute considerably to the damping characteristics of the test damper. Radial forces were also determined at the feeding groove and at the film land for uncavitated flow conditions.

Application of CFD Analysis for Rotating Machinery: Part 1 — Hydrodynamic, Hydrostatic Bearings and Squeeze Film Damper

2003 ◽  
Author(s):  
Zenglin Guo ◽  
Toshio Hirano ◽  
R. Gordon Kirk
Keyword(s):  
Traditional Method ◽  
Reasonable Agreement ◽  
Pressure Field ◽  
Squeeze Film ◽  
Cfd Analysis ◽  
Complex Flow ◽  
Static And Dynamic Characteristics ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Machinery Part

The traditional method for bearing and damper analysis usually involves a development of rather complicated numerical calculation programs that may just focus on a simplified and specific physical model. The application of the general CFD codes may make this analysis available and effective where complex flow geometries are involved or when more detailed solutions are needed. In this study, CFX-TASCflow is employed to simulate various fixed geometry fluid-film bearing and damper designs. Some of the capabilities in CFX-TASCflow are applied to simulate the pressure field and calculate the static and dynamic characteristics of hydrodynamic, hydrostatic and hybrid bearings as well as squeeze film dampers. The comparison between the CFD analysis and current computer programs used in industry has been made. The results show reasonable agreement in general. Some of possible reasons for the differences are discussed. It leaves room for further investigation and improvement on the methods of computation.

Application of CFD Analysis for Rotating Machinery—Part I: Hydrodynamic, Hydrostatic Bearings and Squeeze Film Damper

2005 ◽  
Vol 127 (2) ◽  
pp. 445-451 ◽  
Author(s):  
Zenglin Guo ◽  
Toshio Hirano ◽  
R. Gordon Kirk
Keyword(s):  
Traditional Method ◽  
Reasonable Agreement ◽  
Pressure Field ◽  
Squeeze Film ◽  
Cfd Analysis ◽  
Complex Flow ◽  
Static And Dynamic Characteristics ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers ◽  
Machinery Part

The traditional method for bearing and damper analysis usually involves a development of rather complicated numerical calculation programs that may just focus on a simplified and specific physical model. The application of the general CFD codes may make this analysis available and effective where complex flow geometries are involved or when more detailed solutions are needed. In this study, CFX-TASCflow is employed to simulate various fixed geometry fluid-film bearing and damper designs. Some of the capabilities in CFX-TASCflow are applied to simulate the pressure field and calculate the static and dynamic characteristics of hydrodynamic, hydrostatic, and hybrid bearings as well as squeeze film dampers. The comparison between the CFD analysis and current computer programs used in industry has been made. The results show reasonable agreement in general. Some of the possible reasons for the differences are discussed. It leaves room for further investigation and improvement on the methods of computation.

Evaluation of Rayleigh–Plesset Equation Based Cavitation Models for Squeeze Film Dampers

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Jérôme Gehannin ◽  
Mihai Arghir ◽  
Olivier Bonneau
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Incompressible Fluid ◽  
Pressure Field ◽  
Momentum Equation ◽  
External Pressure ◽  
Squeeze Film ◽  
Cavitation Model ◽  
Squeeze Film Damper ◽  
Squeeze Film Dampers

This work is intended to evaluate a cavitation model based on the complete Rayleigh–Plesset (RP) equation for use in squeeze film damper calculations. The RP equation governs the variation in the radius of the cavitation bubbles at rest, surrounded by an infinite incompressible fluid and subjected to an external pressure. This equation is obtained from the momentum equation and it takes into account the ensemble of the phenomena related to the dynamics of the bubbles (surface tension, damping, and inertia). All the terms in the RP equation will be taken into account in the present work plus a dilatation viscosity introduced by Someya in 2003. Numerical results will be compared with experimental data obtained by Adiletta and Pietra in 2006. The results underline the influence of the effects contained in the RP equation on the pressure field.

Analysis of Short Squeeze Film Dampers With a Central Groove

1992 ◽  
Vol 114 (4) ◽  
pp. 659-664 ◽  
Author(s):  
Luis A. San Andres
Keyword(s):  
Squeeze Film ◽  
Inertia Force ◽  
Dynamic Force ◽  
Fluid Inertia ◽  
Dynamic Flow ◽  
Low Frequencies ◽  
Squeeze Film Damper ◽  
Force Coefficients ◽  
Squeeze Film Dampers ◽  
Combined Action

A novel analysis for the dynamic force response of a squeeze film damper with a central feeding groove considers the dynamic flow interaction between the squeeze film lands and the feeding groove. For small amplitude centered motions and based on the short bearing model, corrected values for the damping and inertia force coefficients are determined. Correlations with existing experimental evidence is excellent. Analytical results show that the grooved-damper behaves at low frequencies as a single land damper. Dynamic force coefficients are determined to be frequency dependent. Analytical predictions show that the combined action of fluid inertia and groove volume—liquid compressibility affects the force coefficients for dynamic excitation at large frequencies.

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